Choice of therapy in intestinal parasitic disease

Abstract

Dr. B. B. Roy: Parasitic diseases of the intestine are numerous and present a variety of problems in regard to incidence, clinical types, economic groups in the population and geographic situations. Indeed the problems of treatment envisage more than the choice of a remedy. The most efficacious therapy is not necessarily the one suitable for adoption in a particular area or instance. Considerations include toxicity, ease of administration, cost and length of medication, and the patient's ability to cooperate in a therapeutic regimen. It can hardly be expected to cover the entire field in one session. Dr. Kean wisely selected for discussion a few of the diseases commonly encountered in the New York City area. However, these are not peculiar to this city but are widely prevalent throughout the world, and this fact has added wider significance to the discussion. This session has been profitable in developing the perspective necessary for an appreciation of the general problems of treatment of parasitic infections of the intestine. A long list of drugs is available for therapy in intestinal infections, some old, some new. The point was made that reported results of various treatments should be regarded with suspicion, inasmuch as initial evaluation seldom presents the ultimate facts. In intestinal amebiasis, because of unsatisfactory results with individual drugs, the treatment plan discussed includes a combination such as emetine, an antibiotic and an arsenical; additionally, in cases of recurrence, a halogenated hydroxyquinone derivative. Details regarding choice of drugs, dosage, length of medication and related problems were outlined and discussed. There was considerable discussion regarding the course to be adopted in cases of asymptomatic amebiasis. The consensus of the Conference was that in view of the public health aspects of the problem and the potential danger of hepatitis such patients should be treated wherever practicable using the same plan suggested for acute amebic dysentery. It was pointed out that these patients who thought they were in good health felt much better after a course of therapy. Other items of interest included the comparative efficacy of aureomycin and terramycin, the role of stress in precipitating attacks of amebic infection by inducing changes in intestinal mucosa and the relationship, if any, between amebiasis and ulcerative colitis, as well as the question of whether cysts formed in the intestine of a host can divide and release trophozoites without crossing the gastric barrier of a new host. In hepatic amebiasis the lesion is a localized abscess and not a diffuse hepatitis. Recently chloroquine has shown promising results but perhaps it is not yet safe to use it to the exclusion of emetine. The effect of terramycin, which is sometimes spectacular, is related to eradication of associated bacterial infections, not to any specific action on amebas. Atabrine, now rarely used as an antimalarial, has recently found two useful applications in the treatment of infections caused by G. lamblia and tapeworm. In the former it is the standard drug. In the latter it is at present preferred to the classic remedy, oleoresin of aspidium. The problem in tapeworm infections is to get a high concentration of the drug to act at the site to which the head of the worm is attached. The mode of administration in this disease is therefore a decisive factor. Details of preparation of the patient, administration of medication and evaluation of the results were fully discussed. In pinworm infection the importance of hygienic measures has been emphasized. Since the life of the female worm is about eight weeks, prevention of reinfection for this period could eradicate the disease by hygienic measures alone. However, it is current practice to combine hygienic measures with drugs. It is noteworthy that enemas, a time-honored favorite, are considered ineffective no matter which drugs may be employed.